Gastrocnemius tendinopathy or tendinitis is inflammation or degeneration of the tendon of the calf muscle causing pain at the back of the knee. This is an overuse injury which is more common in runners and sprinters. Treatment involves reducing the pain and inflammation followed by a full rehabilitation and exercise program to restore the muscle and tendon to full function.
Symptoms include gradual onset pain at the back of the knee. Tenderness will be felt at the origin of the calf muscle and pain is reproduced by resisted bending of the knee (knee flexion). Pain may also be triggered when doing calf raises with a straight leg (only if it is really bad), or hopping on the bad leg. Sometimes doing calf stretches will be painful but not always.
Calf tendinopathy is an overuse injury. The term tendinitis is often used which indicates inflammation. This is more likely if the injury is recent or acute. If it has been coming on gradually then it is possible the injury is more a degeneration of the tendon rather than acute inflammation.
Although overuse such as increasing mileage too soon or doing too much high intensity sprinting is likely to be the cause the chances of sustaining this injury are increased if there is muscle imbalance in the hip or knee joints, or if the athlete has poor foot biomechanics. Wearing incorrect or poorly fitting footwear should also be considered.
Initial treatment consists of applying the PRICE principles of protection, rest, ice, compression, and elevation. Rest is important to protect from further damage and allow the injury to heal. In minor cases, this may initially consist of modifying training, for example, avoiding sprinting if it hurts to run fast, or avoiding running altogether in favour of cycling or similar.
Ice will help reduce pain and inflammation and is very important in the early stages (48 to 72 hours). Once the initial pain and inflammation has gone a gradual stretching and strengthening program should be done. This will ensure the injury does not recur once normal training loads are applied again. A knee support or heat retainer may help by protecting and supporting the area and keeping the tendon warm when returning to training activities.
A professional therapist can make an accurate diagnosis and may use electrotherapy such as ultrasound to help reduce pain and inflammation. A doctor may prescribe anti-inflammatory medication such as Ibuprofen in the early stages to help reduce pain and inflammation, although long-term use is not thought to aid the healing process.
Sports massage to the calf muscles is important to help relax and stretch the muscle which will reduce the strain on the tendon and enable the muscle to function better during activity. Local cross friction massage to the tendon itself may be used in more chronic cases.
Stretching exercises for the calf muscle in particular and the hamstring muscle should be done as soon as pain allows and maintained throughout the rehabilitation process and beyond.
Strengthening exercises for the calf muscles can also begin after the acute stage as long as they can be done pain-free. For more severe injuries this may start with simple plantar flexion exercises with a resistance band and progress to calf raise exercises on a step. Begin with both legs and as strength and confidence improve this can be developed to single leg calf raises.